TW202414538A - Method for manufacturing semiconductor wafer and semiconductor wafer - Google Patents

Abstract

To provide a method for manufacturing a semiconductor wafer containing a carbon-containing silicon layer with no SiC precipitation on a wafer surface and other defects suppressed. A method for manufacturing a semiconductor wafer comprises the steps of: (1) forming a silicon film doped with carbon on a silicon substrate at a first temperature; (2) forming a silicon film not doped with carbon on the silicon film doped with carbon at the first temperature to obtain a stacked wafer; and (3) annealing the stacked wafer at a second temperature higher than the first temperature or further forming a film on the stacked wafer at the second temperature to obtain a semiconductor wafer.

Description

Semiconductor wafer manufacturing method and semiconductor wafer

The present invention relates to a method for manufacturing a semiconductor wafer including a silicon layer, wherein the silicon layer contains carbon.

Silicon (Si) doped with carbon (C) has been found to have properties that are not seen in non-doped Si, such as metal gettering ability and oxygen capture effect. Although various applications to devices can be expected based on the above properties, there is a problem that SiC will precipitate to the surface layer due to heat treatment when Si doped with high concentration of C. When applied to devices, there are many situations where thermal stability is required, such as the need for film formation at high temperatures for annealing or lamination with Si layers, so the thermal instability of Si doped with C is a problem.

In the previous film formation of a silicon layer containing carbon, a method for forming an epitaxial film stack has been proposed (Patent Document 1), in which, when forming an epitaxial layer stack on a substrate, a carbon layer containing a target carbon concentration of 200ppm to 5% of atoms is formed at a temperature below 700°C, and then a cap layer not containing carbon is formed at a temperature below 700°C and etched using an etching gas. However, the need for an additional step such as etching increases the number of steps, resulting in an increase in cost, and the influence of defects on film quality is not discussed.

[Prior technical literature] (Patent literature) Patent literature 1: Japanese Patent No. 5090451

(Problem to be solved by the invention) The present invention was made in view of the above situation, and its purpose is to provide a method for manufacturing a semiconductor wafer including a silicon layer, wherein the silicon layer contains carbon, SiC is not precipitated on the wafer surface, and other defects are also suppressed.

(Means for solving the problem) In order to solve the above problem, the present invention provides a semiconductor manufacturing method, which has the following steps: (1) forming a carbon-doped silicon film on a silicon substrate at a first temperature; (2) forming a non-carbon-doped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a laminated wafer; and (3) annealing the laminated wafer at a second temperature higher than the first temperature, or further forming a film on the laminated wafer at the second temperature, thereby obtaining a semiconductor wafer.

By doing so, a semiconductor wafer including a silicon layer containing carbon, without SiC being precipitated on the surface, and with other defects suppressed can be manufactured by forming a silicon film not doped with carbon at a first temperature.

Furthermore, it is preferred that the first temperature be set to 400°C to 1000°C.

At this time, it is more preferable to set the first temperature to 600°C to 800°C.

It is preferable to form a carbon-doped silicon film and a carbon-undoped silicon film at such a temperature.

Furthermore, it is preferred that the thickness of the silicon film not doped with carbon be 5 nm to 200 nm.

In this case, it is more preferable that the thickness of the silicon film not doped with carbon is set to 5 nm to 50 nm.

If the thickness of the silicon film not doped with carbon is made to be this thickness, the effect of the present invention can be more reliably exerted.

Furthermore, it is preferred that the carbon atom concentration of the carbon-doped silicon film be greater than or equal to 1.0E+17 atoms/cm ³ and less than or equal to 4.5E+22 atoms/cm ³ .

At this time, it is more preferable to make the carbon atom concentration of the carbon-doped silicon film not less than 1.0E+18 atoms/cm ³ and not more than 2.0E+22 atoms/cm ³ .

At this time, it is more preferable to make the carbon atom concentration of the carbon-doped silicon film not less than 1.0E+19 atoms/cm ³ and not more than 5.0E+21 atoms/cm ³ .

It is preferable from a practical point of view that the carbon atom concentration of the carbon-doped silicon film is within such a range.

Furthermore, the present invention provides a semiconductor wafer, which is characterized in that: the semiconductor wafer at least has: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a silicon film not doped with carbon formed on the carbon-doped silicon film; and, the semiconductor wafer has no SiC precipitation on the surface on the side opposite to the lower surface of the silicon substrate.

The semiconductor wafer manufacturing method of the present invention can manufacture a semiconductor wafer including a silicon layer containing carbon that is not degraded by such heat, and the film quality of the silicon film not doped with carbon on the surface of the wafer is also good.

Furthermore, it is preferred that the thickness of the carbon-undoped silicon film is 5 nm to 200 nm.

In this case, it is more preferred that the thickness of the carbon-undoped silicon film is 5 nm to 50 nm.

If the thickness of the silicon film not doped with carbon is of such a thickness, the effect of the present invention can be more reliably exerted.

Furthermore, it is preferred that the carbon atom concentration of the carbon-doped silicon film is greater than or equal to 1.0E+17 atoms/cm ³ and less than or equal to 4.5E+22 atoms/cm ³ .

At this time, it is more preferred that the carbon atom concentration of the carbon-doped silicon film is greater than or equal to 1.0E+18 atoms/cm ³ and less than or equal to 2.0E+22 atoms/cm ³ .

In this case, it is more preferred that the carbon atom concentration of the carbon-doped silicon film is greater than or equal to 1.0E+19 atoms/cm ³ and less than or equal to 5.0E+21 atoms/cm ³ .

If the carbon atom concentration of the carbon-doped silicon film is within this range, it is preferable from a practical point of view.

(Effect of the invention) According to the present invention, after forming a carbon-doped silicon film, a non-carbon-doped silicon film is formed on the aforementioned carbon-doped silicon film at the same temperature, thereby manufacturing a semiconductor wafer which is not subjected to thermal degradation of the carbon-doped silicon film caused by subsequent high-temperature heat treatment, but contains a good-quality carbon-doped silicon layer, and the film quality of the non-carbon-doped silicon film on the surface of the wafer is also good.

As described above, there is a demand for developing a method for manufacturing a semiconductor wafer including a silicon layer containing carbon while preventing degradation due to heat.

As a result of repeated and in-depth studies on the above-mentioned problems, the inventors of the present invention have discovered that, in an epitaxial wafer having a gettering effect, a silicon epitaxial layer doped with carbon to a carbon concentration of 1.0E+17atoms/cm ³ or more and 4.5E+22atoms/cm ³ or less and a silicon epitaxial layer not doped with the above-mentioned carbon are both formed at 700°C and a pressure of 1 to 80 Torr, and then the silicon epitaxial layer to be the active layer of the device is formed at 1080°C. This makes it possible to reduce defects on the surface of the epitaxial layer caused by the epitaxial layer doped with carbon, thereby completing the present invention.

That is, the present invention is a method for manufacturing a semiconductor wafer, comprising the following steps: (1) forming a carbon-doped silicon film on a silicon substrate at a first temperature; (2) forming a non-carbon-doped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a laminated wafer; and (3) annealing the laminated wafer at a second temperature higher than the first temperature, or further forming a film on the laminated wafer at the second temperature, thereby obtaining a semiconductor wafer.

The present invention is described in detail below, but the present invention is not limited to these embodiments.

[Method for manufacturing semiconductor wafer] The method for manufacturing semiconductor wafer of the present invention includes a first embodiment and a second embodiment. In the first embodiment, a carbon-doped silicon film and a carbon-undoped silicon film formed on a silicon substrate at a first temperature are formed on the silicon substrate by steps (1) and (2) to obtain a laminated wafer, and then a film is formed on the laminated wafer at a second temperature higher than the first temperature by step (3). In the second embodiment, steps (1) and (2) are performed in the same manner as the first embodiment to obtain a laminated wafer, and then the laminated wafer is annealed by step (3) at a second temperature higher than the first temperature. Each embodiment is described in detail below with reference to the drawings.

[First Aspect] FIG. 1 shows a flow chart showing an example of the first aspect of the method for manufacturing a semiconductor wafer of the present invention. In the first aspect, a semiconductor wafer is obtained by performing the following steps (1) to (3). The first aspect is described below along FIG. 1.

<Step (1)> As shown in FIG. 1, step (1) is a step of forming a carbon-doped silicon film 2 on a silicon substrate 1 at a first temperature.

The silicon substrate 1 is not particularly limited, and preferably a single crystal silicon substrate. The single crystal silicon substrate is also not particularly limited, and may be a CZ substrate or a FZ substrate. Furthermore, it may be non-doped or doped. In the case of doping, it may be n-type or p-type. In the case of n-type, for example, P, Sb or As may be doped. In the case of p-type, for example, B, Al or Ga may be doped. In addition, the orientation, diameter, resistivity, etc. of the substrate are not particularly limited.

On such a silicon substrate 1, a silicon film (silicon epitaxial layer) 2 doped with carbon is formed at a first temperature, for example, by CVD (chemical vapor deposition), preferably by RP-CVD (reduced pressure CVD). The raw gas used at this time can be, for example, monomethylsilane or trimethylsilane as a carbon source, and dichlorosilane or monosilane as a silicon source. However, the raw gas is not limited to this gas. The film formation temperature at this time is the "first temperature", for example, it can be set to 400 to 1000°C, and preferably 600 to 800°C, but is not limited to this temperature. The concentration of carbon atoms doped in the silicon layer can be adjusted according to the flow rate of the raw gas or the film formation temperature. Furthermore, the pressure during CVD can be set to 1 to 80 Torr (133 to 10640 Pa).

The carbon atom concentration of the carbon-doped silicon film 2 is preferably 1.0E+17atoms/cm ³ or more and 4.5E+22atoms/cm ³ or less, more preferably 1.0E+18atoms/cm ³ or more and 2.0E+22atoms/cm ³ or less, and even more preferably 1.0E+19atoms/cm ³ or more and 5.0E+21atoms/cm ³ or less. In addition, the carbon atom concentration can be confirmed by SIMS (Secondary Ion Mass Spectroscopy).

The film thickness of the carbon-doped silicon film 2 is not particularly limited, and can be, for example, 10 to 1000 nm, preferably 20 to 500 nm, and more preferably 30 to 200 nm.

<Step (2)> As shown in FIG. 1, step (2) is a step of forming a non-carbon-doped silicon film 3 on a carbon-doped silicon film 2 at a first temperature to obtain a laminated wafer 10.

The silicon film (silicon epitaxial layer) 3 not doped with carbon can also be formed, for example, by CVD, preferably RP-CVD (reduced pressure CVD). The raw material gas used at this time is, for example, dichlorosilane or monosilane. However, the raw material gas is not limited to this gas. In addition, the pressure during CVD can be set to 1 to 80 Torr. Among them, the silicon film 3 not doped with carbon is formed at the same temperature (i.e., the first temperature) as the film formation temperature of the above-mentioned silicon film 2 doped with carbon.

In addition, step (1) and step (2) can be performed using the same CVD device or different CVD devices.

The carbon-doped silicon film formed at the first temperature functions as a Si-Cap (silicon cap) layer. When the film is formed at a second temperature higher than the first temperature in the later-described step (3), diffusion of carbon from the carbon-doped silicon film 2 to the upper layer due to the high temperature can be suppressed.

The thickness of the carbon-undoped silicon film 3 can be, for example, 5 nm to 200 nm, and preferably 5 nm to 50 nm. If the thickness is set to this level, diffusion of carbon from the carbon-doped silicon film 2 to the surface of the semiconductor wafer can be more reliably suppressed.

<Step (3)> As shown in FIG. 1, step (3) is a step of further forming a film on the stacked wafer 10 at a second temperature higher than the first temperature, thereby obtaining a semiconductor wafer 100. In addition, the example given in FIG. 1 is to further form a silicon film 4 to become an active layer of the device on the stacked wafer 10, but the layer further formed in this step is not limited to this layer.

The silicon film (silicon epitaxial layer) 4 to be the active layer of the device can also be formed, for example, by CVD, preferably RP-CVD (reduced pressure CVD). The raw material gas used at this time is, for example, dichlorosilane or monosilane. However, the raw material gas is not limited to this gas. In addition, the pressure during CVD can be set to 1 to 80 Torr. In this step, the film formation is performed at a second temperature higher than the first temperature.

The second temperature is not particularly limited as long as it is higher than the first temperature, and can be, for example, 800° C. or higher, and preferably 1000 to 1200° C.

The thickness of the silicon film 4 formed in this step to become the active layer of the device is not particularly limited, and an appropriate thickness can be set according to the application.

In addition, step (3) can be performed using the same CVD apparatus as step (2), or can be performed using a different CVD apparatus.

In the present invention, the film formation using high temperature (second temperature) in step (3) is not performed directly above the carbon-doped silicon film 2, but on the non-carbon-doped silicon film (Si-Cap layer) 3 formed at low temperature (first temperature) on the silicon film 2. In this way, the diffusion of carbon from the carbon-doped silicon film 2 to the upper layer can be suppressed. Therefore, in the semiconductor wafer 100 manufactured according to the present invention, carbon does not diffuse into the silicon film 4 to become the device active layer, that is, there is no precipitation of SiC on the surface of the epitaxial layer.

[Second Aspect] FIG. 2 shows a flow chart showing an example of the second aspect of the method for manufacturing a semiconductor wafer of the present invention. In the second aspect of the method for manufacturing a semiconductor wafer of the present invention, a semiconductor wafer is obtained by performing the following steps (1) to (3). The second aspect is described below along FIG. 2.

<Step (1)> As shown in FIG. 2, step (1) is a step of forming a carbon-doped silicon film 2 on a silicon substrate 1 at a first temperature. Step (1) is the same as that described in the first embodiment above.

<Step (2)> As shown in FIG. 2, step (2) is a step of forming a non-carbon-doped silicon film 3 at a first temperature on a carbon-doped silicon film 2 to obtain a laminated wafer 10. Step (2) is the same as that described in the first embodiment above.

<Step (3)> As shown in FIG. 2, step (3) is a step of annealing the laminated wafer 10 at a second temperature higher than the first temperature to obtain a semiconductor wafer 100.

The second temperature for annealing is not particularly limited as long as it is higher than the first temperature, and can be, for example, 800°C or higher, and preferably 1000 to 1200°C.

In the second aspect, the annealing at high temperature (second temperature) in step (3) is performed after the carbon-free silicon film (Si-Cap layer) 3 is formed at low temperature (first temperature). Therefore, the diffusion of carbon from the carbon-doped silicon film 2 to the upper layer at high temperature can be suppressed as in the first aspect. The semiconductor wafer 100 manufactured according to the second aspect of the present invention also does not have SiC precipitation on the surface of the epitaxial layer.

[Semiconductor wafer] In the present invention, a semiconductor wafer is provided, which is characterized by at least having: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a non-carbon-doped silicon film formed on the carbon-doped silicon film; and no SiC is precipitated on the surface opposite to the lower surface of the aforementioned silicon substrate.

The semiconductor wafer of the present invention can also form another epitaxial layer on the silicon film not doped with carbon, for example, a silicon film to be used as an active layer of a device.

The semiconductor wafer of the present invention can be manufactured by the above-mentioned method for manufacturing the semiconductor wafer of the present invention. Therefore, the diffusion of carbon from the carbon-doped silicon film is suppressed by the carbon-undoped silicon film formed thereon, so that SiC will not precipitate on the surface of the epitaxial layer.

Therefore, the semiconductor wafer of the present invention has metal absorption capability or oxygen capture effect, RF (radio frequency) characteristics improvement effect, and the silicon film not doped with carbon on the surface is also of high quality, so it can be applied to various devices (RF devices or CIS (CMOS image sensor)).

[Example] The present invention is specifically described below using examples and comparative examples, but the present invention is not limited to these examples. In addition, in the following examples and comparative examples, the number of LLS (local light scattering) defects is measured using SP3 manufactured by KLA Tencor as the defect evaluation on the surface of the semiconductor wafer.

In the following Examples 1 to 8, steps (1) to (3) of the method for manufacturing a semiconductor wafer of the present invention are performed as shown in the flow chart of FIG3. On the other hand, in the following Comparative Examples 1 to 7, only steps (1) and (3) of the method for manufacturing a semiconductor wafer of the present invention are performed as shown in the flow chart of FIG3, and step (2) is not performed.

(Example 1) Using RP-CVD, under the conditions of 700°C and 5 Torr, in a mixed gas environment containing SiH ₄ and SiH(CH ₃ ) ₃ , a 100nm C-doped Si layer (carbon atom concentration: 1.0E+20atoms/cm ³ ) was grown on a silicon substrate. Then, a 30nm C-undoped Si layer (Si-cap layer) was grown at 700°C. After that, the temperature was raised to 1080°C to grow the Si layer and manufacture a semiconductor wafer. At this time, the LLS was 16 in 32nmup.

(Example 2) As a semiconductor wafer to be evaluated, the thickness of the C non-doped Si layer (Si-cap layer) was made 10nm, and the semiconductor wafer was manufactured under the same conditions as Example 1. At this time, the number of LLS in 32nmup was 25.

(Example 3) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Example 1 except that the carbon atom concentration was set to 3.0E+21 atoms/cm ³ . In this case, the number of LLSs was 15 in 32 nmup.

(Example 4) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Example 1 except that the carbon atom concentration was set to 8.0E+21 atoms/cm ³ . At this time, the number of LLSs in 32 nmup was 165.

(Example 5) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Example 1 except that the carbon atom concentration was set to 2.5E+22 atoms/cm ³ . At this time, the number of LLSs in 32 nmup was 861.

(Example 6) Using RP-CVD, under the conditions of 850°C and 5 Torr, in a mixed gas environment containing SiH ₄ and SiH ₃ (CH ₃ ), a 100nm C-doped Si layer (carbon atom concentration: 2.0E+19atoms/cm ³ ) was grown on a silicon substrate. Then, a 30nm C-undoped Si layer (Si-cap layer) was grown at 850°C. After that, the temperature was raised to 1080°C to grow the Si layer to manufacture a semiconductor wafer. At this time, the LLS was 6 in 32nmup.

(Example 7) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Example 6 except that the carbon atom concentration was set to 2.0E+18 atoms/cm ³ . In this case, the number of LLSs in 32 nmup was 26.

(Example 8) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Example 6 except that the carbon atom concentration was set to 4.0E+17 atoms/cm ³ . In this case, the number of LLSs in 32 nmup was 12.

(Comparative Example 1) Using RP-CVD, at 700°C and 5Torr, in a mixed gas environment containing SiH ₄ and SiH(CH ₃ ) ₃ , a 100nm C-doped Si layer (carbon atom concentration: 1.0E+20atoms/cm ³ ) is grown on a silicon substrate. Then, the temperature is raised to 1080°C to grow the Si layer and manufacture a semiconductor wafer. At this time, LLS is in an overload state in 32nmup. In addition, overload means that LLS is about 30,000 or more per wafer.

(Comparative Example 2) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 1 except that the carbon atom concentration was set to 3.0E+21 atoms/cm ³ . At this time, LLS was in an overload state in 32nmup.

(Comparative Example 3) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 1 except that the carbon atom concentration was set to 8.0E+21 atoms/cm ³ . At this time, LLS was in an overload state in 32nmup.

(Comparative Example 4) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 1 except that the carbon atom concentration was set to 2.5E+22 atoms/cm ³ . At this time, LLS was in an overload state in 32nmup.

(Comparative Example 5) Using RP-CVD, at 850°C and 5 Torr, in a mixed gas environment containing SiH ₄ and SiH ₃ (CH ₃ ), a 100nm C-doped Si layer (carbon atom concentration: 2.0E+19atoms/cm ³ ) was grown on a silicon substrate. Then, the temperature was raised to 1080°C to grow the Si layer and manufacture a semiconductor wafer. At this time, LLS was in an overload state in 32nmup.

(Comparative Example 6) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 5 except that the carbon atom concentration was set to 2.0E+18 atoms/cm ³ . At this time, LLS was in an overload state in 32nmup.

(Comparative Example 7) As a semiconductor wafer to be evaluated, a semiconductor wafer was manufactured under the same conditions as in Comparative Example 5 except that the carbon atom concentration was set to 4.0E+17 atoms/cm ³ . At this time, LLS was in an overload state in 32nmup.

The results of Examples 1 to 8 and Comparative Examples 1 to 7 are summarized in Table 1.

[Table 1] Carbon concentration (atoms/cm ³ ) 30nm Si cap layer (Examples 1, 3 to 8) 100nm Si cap layer (Example 2) No Si cap layer (Comparative Examples 1 to 7) 4.0E17 12 - Overload 2.0E18 26 - Overload 2.0E19 6 - Overload 1.0E20 16 25 Overload 3.0E21 15 - Overload 8.0E21 165 - Overload 2.5E22 861 - Overload

It can be clearly seen from Table 1 that the semiconductor wafers manufactured by the semiconductor wafer manufacturing method of the present invention as in Examples 1 to 8 have no SiC precipitation on the surface of the epitaxial layer and very few LLS, and the diffusion of carbon is suppressed by the Si-Cap layer. In particular, when the carbon concentration of the C-doped Si layer is below 3.0E21atoms/ ^cm3 , excellent results are particularly achieved. On the other hand, in Comparative Examples 1 to 7, step (2) of the present invention is not implemented, but the device active layer is directly formed at a high temperature on the C-doped Si layer, so that carbon diffuses from the C-doped Si layer and SiC is precipitated on the surface of the device active layer, resulting in a very large number of LLS (overload).

This specification contains the following inventions.

[1]: A method for manufacturing a semiconductor wafer comprises the following steps: (1) forming a carbon-doped silicon film on a silicon substrate at a first temperature; (2) forming a non-carbon-doped silicon film on the carbon-doped silicon film at the first temperature, thereby obtaining a laminated wafer; and (3) annealing the laminated wafer at a second temperature higher than the first temperature, or further forming a film on the laminated wafer at the second temperature, thereby obtaining a semiconductor wafer.

[2]: The method for manufacturing a semiconductor wafer as described in [1] above, wherein the first temperature is set to 400°C to 1000°C.

[3]: The method for manufacturing a semiconductor wafer as described in [1] or [2] above, wherein the first temperature is set to 600°C to 800°C.

[4]: The method for manufacturing a semiconductor wafer as described in [1], [2] or [3] above, wherein the thickness of the carbon-undoped silicon film is set to 5 nm to 200 nm.

[5]: The method for manufacturing a semiconductor wafer as described in [1], [2], [3] or [4] above, wherein the thickness of the carbon-undoped silicon film is set to 5 nm to 50 nm.

[6]: A method for manufacturing a semiconductor wafer as described in [1], [2], [3], [4] or [5] above, wherein the carbon atom concentration of the carbon-doped silicon film is set to be greater than 1.0E+17 atoms/ ^cm3 and less than 4.5E+22 atoms/ ^cm3 .

[7]: A method for manufacturing a semiconductor wafer as described in [1], [2], [3], [4], [5] or [6] above, wherein the carbon atom concentration of the carbon-doped silicon film is set to be greater than 1.0E+18 atoms/ ^cm3 and less than 2.0E+22 atoms/ ^cm3 .

[8]: A method for manufacturing a semiconductor wafer as described in [1], [2], [3], [4], [5], [6] or [7] above, wherein the carbon atom concentration of the carbon-doped silicon film is set to be greater than 1.0E+19 atoms/ ^cm3 and less than 5.0E+21 atoms/ ^cm3 .

[9]: A semiconductor wafer, characterized in that: the semiconductor wafer at least comprises: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a non-carbon-doped silicon film formed on the carbon-doped silicon film; and the semiconductor wafer has no SiC precipitation on the surface opposite to the lower surface of the silicon substrate.

[10]: The semiconductor wafer as described in [9] above, wherein the thickness of the carbon-undoped silicon film is 5 nm to 200 nm.

[11]: The semiconductor wafer as described in [9] or [10] above, wherein the thickness of the carbon-undoped silicon film is 5 nm to 50 nm.

[12]: A semiconductor wafer as described in [9], [10] or [11] above, wherein the carbon atom concentration of the carbon-doped silicon film is greater than or equal to 1.0E+17 atoms/cm ³ and less than or equal to 4.5E+22 atoms/cm ³ .

[13]: A semiconductor wafer as described in [9], [10], [11] or [12] above, wherein the carbon atom concentration of the carbon-doped silicon film is greater than or equal to 1.0E+18 atoms/cm ³ and less than or equal to 2.0E+22 atoms/cm ³ .

[14]: A semiconductor wafer as described in [9], [10], [11], [12] or [13] above, wherein the carbon atom concentration of the carbon-doped silicon film is greater than or equal to 1.0E+19 atoms/cm ³ and less than or equal to 5.0E+21 atoms/cm ³ .

In addition, the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are illustrative, and any embodiments having substantially the same structure and exerting the same function and effect as the technical concept described in the patent application scope of the present invention are included in the technical scope of the present invention.

1: Silicon substrate 2: Silicon film 3: Silicon film 4: Silicon film 10: Laminated wafer 100: Semiconductor wafer

FIG. 1 is a flowchart showing an example of a first aspect of the method for manufacturing a semiconductor wafer of the present invention. FIG. 2 is a flowchart showing an example of a second aspect of the method for manufacturing a semiconductor wafer of the present invention. FIG. 3 is a flowchart showing the film formation of the semiconductor wafer in the embodiment and the comparative example.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

1: Silicon substrate

2: Silicon film

3:Silicon film

4: Silicon film

Claims (14)

A method for manufacturing a semiconductor wafer comprises the following steps: (1) forming a carbon-doped silicon film at a first temperature on a silicon substrate; (2) forming a non-carbon-doped silicon film at the first temperature on the carbon-doped silicon film, thereby obtaining a laminated wafer; and (3) annealing the laminated wafer at a second temperature higher than the first temperature, or further forming a film on the laminated wafer at the second temperature, thereby obtaining a semiconductor wafer. A method for manufacturing a semiconductor wafer as described in claim 1, wherein: The first temperature is set to 400°C to 1000°C. A method for manufacturing a semiconductor wafer as described in claim 2, wherein: The first temperature is set to 600°C to 800°C. A method for manufacturing a semiconductor wafer as described in claim 1, wherein: The thickness of the aforementioned silicon film not doped with carbon is made to be 5nm to 200nm. A method for manufacturing a semiconductor wafer as described in claim 4, wherein: The thickness of the aforementioned silicon film not doped with carbon is made to be 5nm to 50nm. A method for manufacturing a semiconductor wafer as described in claim 1, wherein: the carbon atom concentration of the carbon-doped silicon film is set to be greater than 1.0E+17 atoms/cm ³ and less than 4.5E+22 atoms/cm ³ . A method for manufacturing a semiconductor wafer as described in claim 6, wherein: the carbon atom concentration of the carbon-doped silicon film is set to be greater than 1.0E+18 atoms/cm ³ and less than 2.0E+22 atoms/cm ³ . A method for manufacturing a semiconductor wafer as described in claim 7, wherein: the carbon atom concentration of the carbon-doped silicon film is set to be greater than 1.0E+19 atoms/cm ³ and less than 5.0E+21 atoms/cm ³ . A semiconductor wafer, characterized in that: The semiconductor wafer at least has: a silicon substrate having an upper surface and a lower surface; a carbon-doped silicon film formed on the upper surface of the silicon substrate; and a non-carbon-doped silicon film formed on the carbon-doped silicon film; and, The semiconductor wafer has no SiC precipitation on the surface opposite to the lower surface of the silicon substrate. A semiconductor wafer as described in claim 9, wherein: The thickness of the aforementioned silicon film not doped with carbon is 5nm to 200nm. A semiconductor wafer as described in claim 10, wherein: The thickness of the aforementioned silicon film not doped with carbon is 5nm to 50nm. A semiconductor wafer as described in claim 9, wherein: the carbon atom concentration of the carbon-doped silicon film is greater than 1.0E+17 atoms/cm ³ and less than 4.5E+22 atoms/cm ³ . A semiconductor wafer as described in claim 12, wherein: the carbon atom concentration of the carbon-doped silicon film is greater than 1.0E+18 atoms/cm ³ and less than 2.0E+22 atoms/cm ³ . A semiconductor wafer as described in claim 13, wherein: the carbon atom concentration of the carbon-doped silicon film is greater than 1.0E+19 atoms/cm ³ and less than 5.0E+21 atoms/cm ³ .